This is the preview of Neverwinter Nights as included with the game Baldur's Gate II. It shows off early footage from the game, and several concept art shots. Since it likely hadn't been decided at the time, no mention of the plot or class features, or the intricacies of the design are mentioned.
Run time 00:01:04Producer BiowareProduction Company BiowareAudio/Visual MPEG Audio 44100Hz stereo 256Kbps, MPEG1 Video 352x240 (107:80) 29.97fps 1500KbpsLanguage English
Unlike the later trailers for the game which included more final shots, this preview also dates back to when Black Isle software was producing the game. The date of the video according to the disk is 28 July 2000, 11:30:48, somewhat before the Baldur's Gate II release date of September 2000.